Power operated crutches having lengthwise extensible/retractable motion are known, and have been the subject of U.S. Pat. Nos. 3,157,188, 3,157,189, 3,416,546, and 4,237,916. All of those are fitted with conventional tips, generally in the form of an elastomeric cup fitted to the bottom of the crutch post and intended to provide a somewhat resilient minimized slip contact with the underlying floor, pavement, etc. Other patents disclose pivoting or conforming tips which may include a somewhat enlarged floor contact member to make an enlarged "footprint" contact and also provide limited 360.degree. motion of the contact member with respect to the crutch tip, so as to maintain an extended area contact as the post is tilted during use of the crutch. Typical such patents are patent Nos. 2,230,406, and 679,468, as well as No. 2,351,145 which relates to stilts.
The prior art does not, however, address the need for a power operated crutch construction which can assist a handicapped person, particularly a paraplegic or similarly afflicted person, to rise from sitting to standing positions (and similarly to sit from a standing position) with additional assistance. Such persons, provided they have sufficient upper body strength, which many do have, can walk with crutches if they are fitted with a so-called full body brace. This is a generally available hinged metal (or equivalent) brace which has the capability of locking knee and hip joints in a straight line, so the person so fitted can stand on his/her legs without fear of collapsing, and can swing the lower torso between appropriate crutches and thus be self-ambulatory once achieving a standing position between the crutches.
By way of background explanation, such braces include a waist encircling upper part, which can be firmly attached to the wearer's torso above the hips, and linkages extending downward along the hips and legs. These linkages include joints at the location of the person's hip joints, which joints can be locked and unlocked, joints adjacent the person's knees, which also can be locked and unlocked, and lower supports which receive and attach to the calves, ankle joints and feet of the wearer. With the aforementioned joints unlocked, the various links pivot to allow movement of the person's legs to a seated position. With the links along the legs extended and locked, the persons legs are supported in an extended position. With the person standing erect, and the hip joints of the brace locked, the persons legs are supported in line with the upper torso.
Thus, there is a need for power operated crutches which have capability of assisting persons using such a brace in transition between seated and standing positions without additional help, thereby considerably enhancing such persons' mobility and self reliance.